Re-pairing strategy for mode-pairing quantum key distribution

The article delves into the evolution of quantum key distribution (QKD), a technology that leverages quantum mechanics to secure communication channels. It highlights the challenges posed by transmission losses and the limitations of existing protocols, such as the PLOB bound. The study introduces a groundbreaking re-pairing strategy for mode-pairing QKD (MP-QKD), which addresses these challenges by recycling discarded click events to improve parameter estimation. This innovative approach, combined with the double-scanning method, achieves superior key rate performance and extends transmission distances, as demonstrated through comprehensive simulations. The article provides a detailed analysis of the MP-QKD protocol, including state preparation, pulse transmission, interference detection, and post-data processing. It also compares the new re-pairing strategy with existing methods, showcasing its advantages in enhancing the efficiency and security of QKD implementations. The simulation results underscore the potential of the proposed strategy to surpass the PLOB bound, making it a significant contribution to the field of quantum communication.